Preparation method of high-voltage ceramic capacitor copper electrode

Abstract

The invention discloses a preparation method of a copper electrode of a high-voltage ceramic capacitor. The preparation method comprises the following steps: attaching copper oxide slurry to the surface of a sintered high-voltage ceramic capacitor porcelain body to form a pretreated capacitor porcelain body; placing the pretreated capacitor porcelain body between two layers of graphite felts, and placing the pretreated capacitor porcelain body in a vacuum box for vacuumizing; applying voltage and current to the graphite felt to generate Joule heat to reduce copper oxide into a copper electrode; and carrying out a post-treatment process on the prepared copper electrode. According to the method, voltage and current are directly applied to the graphite felt, the reduction reaction of high-temperature carbon and surface electrode copper oxide is achieved in vacuum, copper oxide is reduced into copper, the electrode preparation time is greatly shortened, energy consumption of traditional electrode preparation is reduced, and the electrode preparation efficiency is improved; pure copper oxide is used as an electrode material, and no organic carrier material is added, so that environmental pollution is avoided, and green production is realized; inert gas protection is not needed in the preparation process of the electrode, and the process is simple and safe.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic capacitors, and particularly relates to a preparation method of a high-voltage ceramic capacitor copper electrode. BACKGROUND

[0002] Traditional high-voltage ceramic capacitor electrodes are prepared using noble metal electrode materials such as gold and silver, which have high costs, while using relatively low-cost base metal copper as the electrode material has the defect that the copper surface is easily oxidized to form copper oxide, which greatly limits the application of copper electrodes in high-voltage ceramics.

[0003] Currently, although some studies have attempted to solve the oxidation problem of copper electrodes in high-voltage ceramics, such as:

[0004] Patent CN 117373825 A discloses a preparation method of an MLCC capacitor copper end electrode, which uses inert gas argon and vacuum protection to sputter a copper electrode layer. The copper end electrode preparation method used in this method requires high-cost sputtering equipment, needs inert gas and vacuum double-layer protection for copper electrode oxidation, and the operation process is relatively complex.

[0005] Patent CN 117116659 A discloses a preparation method of a copper inner electrode type ceramic MLCC, which prints copper inner electrode paste on a ceramic diaphragm through screen printing, stacks to form a green body, and then performs vacuum lamination, cutting, degassing, nitrogen and hydrogen sintering, chamfers the ceramic capacitor, soaks the copper electrode paste, and nitrogen sintering for 8-15 minutes. Although this method avoids copper electrode oxidation, the operation process is complex, time-consuming, and the use of hydrogen requires special safety management and supervision.

[0006] Patent CN 117316639 A discloses a copper inner electrode paste for a multilayer antiferroelectric ceramic capacitor and a preparation method thereof, which uses 55-70wt% SiO2 to wrap nano-submicron copper powder, mixes 0.1-3wt% glass powder, 1.5-8wt% inorganic ceramic powder, and 25-45wt% organic carrier (containing methanol, etc.) to prepare a copper paste mixture. Although this method avoids copper electrode oxidation, the organic carrier has a relatively large proportion and contains toxic substances, which poses certain harm and pollution to the operator's body and environment, and the prepared copper paste mixture also needs to be coated and sintered on the surface of the ceramic capacitor, which is a complex process.

[0007] The above-mentioned various studies on the manufacture of base metal copper as a high-voltage ceramic electrode all have the defects of complex process, insecurity, and long time-consuming.

[0008] The present application aims to provide a simple and effective and low-cost high-voltage ceramic capacitor copper electrode preparation method, to overcome the deficiencies in the prior art, to promote the wide application of copper electrode in the field of high-voltage ceramic, to reduce the electrode preparation cost, to meet the market demand for high-voltage ceramic capacitors. SUMMARY

[0009] In view of the deficiencies in the prior art, the present application aims to provide a high-voltage ceramic capacitor copper electrode preparation method to solve the problems of complex preparation process, insecurity, long time-consuming and the like when using base metal copper as electrode material to reduce the cost of high-voltage ceramic capacitors.

[0010] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0011] A high-voltage ceramic capacitor copper electrode preparation method, comprising the following steps:

[0012] First step: attaching copper oxide paste to the surface of the sintered high-voltage ceramic capacitor body to form a pretreated capacitor body;

[0013] Second step: placing the pretreated capacitor body between two layers of graphite felt and placing it in a vacuum box to vacuumize;

[0014] Third step: applying voltage and current to the graphite felt to generate Joule heat to reduce the copper oxide to copper electrode;

[0015] Fourth step: post-processing the prepared copper electrode.

[0016] Further, the first step of attaching copper oxide paste adopts coating, printing, casting or sputtering process.

[0017] Further, the thickness of the copper oxide paste in the first step is 10-50um.

[0018] Further, the size of the graphite felt in the second step needs to completely cover the electrode surface of the high-voltage ceramic capacitor body.

[0019] Further, the vacuumization in the second step should make the vacuum degree less than 10 -3 Torr.

[0020] Further, the temperature of the Joule heat generated by the voltage and current in the third step is 1100-1200℃, and the holding time is 1-2.5min.

[0021] Further, the voltage in the third step is 10-24V, and the current is 16-28A.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] 1. The low-cost copper electrode preparation method of this invention involves directly applying voltage and current to graphite felt, and the copper oxide on the surface electrode undergoes a reduction reaction in a vacuum with the help of high-temperature carbon, reducing the copper oxide to copper. This electrode preparation can be completed in less than three minutes, while using a traditional sintering furnace to reduce metal oxides to pure metal takes several hours. In comparison, the preparation method of this invention significantly shortens the electrode preparation time, improves the electrode preparation efficiency, and reduces the energy consumption of traditional electrode preparation.

[0024] 2. This invention uses base metal copper as the electrode material, which significantly reduces the cost of precious metal electrode materials such as gold and silver in high-voltage ceramic capacitors.

[0025] 3. This invention uses pure copper oxide as the electrode material without adding any organic carrier material, thus avoiding environmental pollution and achieving green production.

[0026] 4. The electrode of the present invention does not require the use of inert gas protection during the preparation process, and the process is simple and safe. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the high-voltage ceramic copper electrode preparation method of the present invention;

[0028] Wherein: 1—the ceramic body of the high-voltage ceramic capacitor; 2—the electrode; 3—the graphite felt. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] This invention provides a method for preparing the copper electrode 2 of a high-voltage ceramic capacitor. Specifically, the method involves first attaching copper oxide paste to the sintered high-voltage ceramic capacitor body 1 to form a pretreated capacitor body. The attachment method can be coating, printing, casting, or sputtering. Then, the pretreated capacitor body is placed between two layers of graphite felt 3 and placed in a vacuum chamber for vacuuming, with the vacuum level preferably less than 10. -3 The graphite felt 3 needs to completely cover the surface of the electrode 2 on the ceramic body 1 of the high-voltage ceramic capacitor. Then, voltage and current are applied to the graphite felt 3, utilizing the generated Joule heating temperature to reduce copper oxide to copper electrode 2. Finally, the prepared copper electrode 2 undergoes post-processing. This invention employs a low-cost copper electrode preparation method that directly applies voltage and current to the graphite felt 3, instantly reaching a high temperature. The graphite felt 3 releases carbon elements, and the copper oxide electrode 2 attached to the surface of the high-voltage ceramic capacitor 1 undergoes a reduction reaction in a vacuum using the high-temperature carbon, thereby reducing copper oxide to copper. The specific reaction is shown in formula (1-1). This invention can control the rate of electrode reduction by adjusting the degree of carburization diffusion and the Joule heating temperature through adjusting the vacuum level, voltage, and current.

[0031]

[0032] Example 1

[0033] A method for preparing a high-voltage ceramic capacitor copper electrode, which is prepared according to the following steps:

[0034] Step 1: coating 50 microns of copper oxide paste on the surface of the sintered high-voltage ceramic capacitor body 1 to form a pretreated capacitor body;

[0035] Step 2: placing the pretreated capacitor body between two layers of graphite felt 3 and placing it in a vacuum box to vacuum to a vacuum degree less than 10 -3 Torr;

[0036] Step 3: applying voltage and current to the graphite felt 3, the voltage is 18V and the current is 16A, so that the graphite felt 3 reaches the joule heat temperature 1100℃, and the CuO is reduced to Cu electrode 2 for 2.5min;

[0037] Step 4: post-processing the prepared Cu electrode 2.

[0038] Example 2

[0039] A method for preparing a high-voltage ceramic capacitor copper electrode, which is prepared according to the following steps:

[0040] Step 1: flow casting 20 microns of copper oxide paste on the surface of the sintered high-voltage ceramic capacitor body 1 to form a pretreated capacitor body;

[0041] Step 2: placing the pretreated capacitor body between two layers of graphite felt 3 and placing it in a vacuum box to vacuum to a vacuum degree less than 10 -3 Torr;

[0042] Step 3: applying voltage and current to the graphite felt 3, the voltage is 14V and the current is 24A, so that the graphite felt 3 reaches the joule heat temperature 1190℃, and the CuO is reduced to Cu electrode 2 for 1.5min;

[0043] Step 4: post-processing the prepared Cu electrode 2.

[0044] Example 3

[0045] A method for preparing a high-voltage ceramic capacitor copper electrode, which is prepared according to the following steps:

[0046] Step 1: sputtering 10 microns of copper oxide paste on the surface of the sintered high-voltage ceramic capacitor body 1 to form a pretreated capacitor body;

[0047] Second step: Put the pre-treatment capacitor porcelain body between two layers of graphite felt 3, and place it in a vacuum box to vacuum to a vacuum degree less than 10 -3 Torr;

[0048] Third step: Apply voltage and current to the graphite felt 3, the voltage is 10V, the current is 28A, so that the graphite felt 3 reaches the Joule heat temperature 1200℃, and the CuO is reduced to Cu electrode 2 for 1min;

[0049] Fourth step: Perform post-processing process on the prepared Cu electrode 2.

[0050] Example 4

[0051] A preparation method of a high-voltage ceramic capacitor copper electrode, which is prepared according to the following steps:

[0052] First step: Screen print 35-micron copper oxide paste on the surface of the sintered high-voltage ceramic capacitor porcelain body 1 to form a pre-treatment capacitor porcelain body;

[0053] Second step: Put the pre-treatment capacitor porcelain body between two layers of graphite felt 3, and place it in a vacuum box to vacuum to a vacuum degree less than 10 -3 Torr;

[0054] Third step: Apply voltage and current to the graphite felt 3, the voltage is 24V, the current is 20A, so that the graphite felt 3 reaches the Joule heat temperature 1150℃, and the CuO is reduced to Cu electrode 2 for 2min;

[0055] Fourth step: Perform post-processing process on the prepared Cu electrode 2.

[0056] The preparation time of the entire electrode in the above example can be completed in less than three minutes, while it takes about several hours to reduce metal oxide to pure metal using the traditional sintering furnace reduction process. Compared with the prior art, the preparation method of the present application greatly shortens the preparation time of the electrode, reduces the energy consumption of the traditional electrode preparation, and improves the electrode preparation efficiency. Moreover, the electrode of the present application does not need to be protected by inert gas during preparation, and the process is simple and safe. Furthermore, the present application uses pure copper oxide as electrode material without adding any organic carrier material, avoiding environmental pollution and realizing green production. In addition, the use of base metal copper as electrode material greatly reduces the cost of noble metal electrode materials such as gold and silver in high-voltage ceramic capacitors.

[0057] The above examples are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical range disclosed in the present application can be easily thought of by those skilled in the art, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a copper electrode for a high-voltage ceramic capacitor, characterized in that, Includes the following steps: Step 1: Apply copper oxide paste to the surface of the sintered high-voltage ceramic capacitor body to form a pretreated capacitor body; Step 2: Place the pre-treated ceramic capacitor between two layers of graphite felt and place it in a vacuum chamber to evacuate the vacuum. Step 3: Apply voltage and current to the graphite felt to generate Joule heating and reduce copper oxide to copper electrodes; Step 4: Post-processing of the prepared copper electrode.

2. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 1, characterized in that, The thickness of the copper oxide slurry in the first step is 10-50 μm.

3. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 2, characterized in that, The copper oxide paste applied in the first step is applied using coating, printing, casting, or sputtering processes.

4. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 1, characterized in that, The size of the graphite felt in the second step needs to completely cover the electrode surface of the high-voltage ceramic capacitor.

5. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 4, characterized in that, The second step of vacuuming should result in a vacuum level of less than 10. -3 Torr.

6. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 1, characterized in that, The Joule heating temperature generated by applying voltage and current in the third step is 1100-1200℃, and the holding time is 1-2.5min.

7. The method for preparing the copper electrode of the high-voltage ceramic capacitor according to claim 6, characterized in that, The voltage in the third step is 10-24V and the current is 16-28A.

Images